Method of effecting and regulating combustion in furnaces.



4 F. H. BROWN.

METHOD OF EFFECTING AND REGULATING COMBUSTION IN FURNACES.

APPLlCATlON FILED JULY 3. T913 RENEWED APR. I8, 19!?- 1 %,21, Patented Nov. 20, 191?.

2 SHEETS--SHEET ATTORNEYS F H. BROWN.

METHOD OF EFFECTING AND REGULATING COMBUSTION EN FURNACES.

APPLICATION FILED JULY 8,1913- RENEWED APR. 18. I9!!- hfil 5., Patented Nov. 20, 191?.

2 SHEETS-SHEET 2.

ATTORNEYS enr- FRANCIS H. BnowN, on PHILADELPHIA, PENNSYLVANIA.

METHOD or EFFECTING AND REGULATING ooMBUsTIo Il\T rUn 'AcEs.

Specification of Letters Patent.

Patented Nov. 2t), 1917.

Gontinuation of application Serial No. 662,814, filed November 28, 1911. This application filed July 8, 1913,

x Serial No. 777,811. Renewed April 18, 1917. Serial No. 163,034.

To all whom it may concern:

Be it known that I, FRANCIS H. BROWN, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia, State of Pennsylvania, have invented a new and useful Method of Efl'ecting and Regulating Combustion in Furnaces, of which the following is a specification.

My present invention, in its broad and generic scope, consists of a novel method of effecting and regulating combustion in a furnace or in furnaces, operating under an induced draft, naturally or mechanically produced, whereby a single fire or a plurality of fires with beds of fuel of different and varying thickness will automatically maintain substantially the same rate of combustion and also a substantially fixedor constantdifierence ofdraft pressure or tension above and beneath the bed or beds of "fuel, and thereby reduce to a minimum the amount of air employed to produce combustion.

It further consists of a novel method of regulating combustion wherein the variations of load of a furnace or furnaces or variations in steam pressure are utilized to automatically vary the conditions within the furnace or ,furnaces or the heat zone thereof and then the conditions varied in this manner are utilized together with the varying resistance offered to the introduction of draft beneath the bed of fuel to automatically vary the amount of draft for combustion. The varying resistance offered the introduction of draft beneath a bed of fuel may be the varying thickness of the bedof fuel, a partially closed damper, or a combination of such conditions.

The damper or dampers, which are oper-r ated tovary the conditions within the furnace, may be manually controlled to vary the conditions within a furnace or furnaces and then the introduction ofdraft beneath the bed or beds of fuel automatically controlled in accordance With the varying conditions within the furnace thus formed, and such operatlon is within the spirlt and scope of my invention.

Each exhaust flue or stackmay discharge, "individually, as shown, or they may all be connected to a main exhaust flue or chimney, in which latter case the means for mechanically inducing the draft or for varying the .or mechanical induced draft is employed.

Many different types of mechanism can be used to produce the mechanical induced draft, and it is immaterial whether hand firing orme'chanical stokers or fuel feeding means are employed, and the type of fuel used, whether solid, liquid, gaseous, or a combination of any of the same is also immaterial, and it is to be understood that my claims herein are to be construed as 'of corresponding scope.

In a copending ap'plicatioml have disclosed and generically claimed a novel method of regulating combustion, wherein the variations of load on a furnace or furnaces are utilized to automatically vary the conditions within the furnace or furnaces, and then the varying conditions within the furnace or furnaces are utilized to automatically control the introduction of draft for combustion, and my present invention, while of, the same generic scope, is differentiated from the above in that I dispense with the necessity of employing a forced draft and employ in lieu thereof an induced draft, either natural or mechanical.

It further consists of a novel method of regulating combustion, whereby high temperatures may be maintained within the furnace and a maximum efficiency at all rates of combustion.

Other features of advantage and operation will more clearly hereinafter appear in the detailed description of my invention.

For the purpose of illustrating one manner of advantageously carrying out my novel method in practice, I have shown herein forms thereof which have been found in practice to give satisfactory and reliable results, although it is to be understood that the various instrumentalities of which my invention consists can be variously arranged and organized and that my invention is not limited to use with the precise arrangement and'onganization of these instrumentalities,

as herein shown and described.

other type of mechanism for producing a -.mechanically induced draft.

Fig. 5 represents a sectional view of the arts seen in Fig. 1, but showing. a hand ing arrangement instead of the mechanical stoker seen in Fig. 1.

Fig. 6 represents an elevation, partly in section, of Fig. 5.

Fig. 7 represents a perspective of certain details of construction, seen in Fig. 5.

Fig. 8 represents a sectional elevation of a portion of furnaces having the individual exhaust conduits discharging into a main exhaust conduit, or stack.

Similar numerals of reference indicate corresponding parts in the figures.

Referring to the drawings p 1 designates furnaces of any desired or conventional type and which, in the present instance, are each provided with an ash-pit 2, a travelin grate 3, which acts as a stoker or fuel feeding means, a combustion chamber or heat zone 4 on one side of a bed of fuel 5, a boiler 6, an individual stack 7, and a main header 8, it being understood that, in the present instance, I have shown a battery of boilers and a plurality of furnaces, as will bebest understood by reference ates the main to Figs. 5 and 8. 9 desi is supplied undraft conduit, to which dra der its natural or atmospheric pressure, provided with a manually controlleddamper 10 and from conduit 19 lead branch conduits 11, which are in communication with the ash-pits 2 of their respective furnace, and each. of which is provided with a manually, controlled damper 12. 13 designates a steam conduit communicating with the main header 8 and with a steam regulator 140i any desired or conventional type, and illustrated as of the well known diaphragm type, said conduit 13 being provided with a manually controlled valve 15. 16 designates a rod which is actuated in the well known manner, by the diaphragm, in accordance with the variations in the steam pressure to rock the lever 17 on its pivot 18, said lever 17 being provided with an adjustable counterbalance 19, whereby the effective weight of the counterbalance may be varied as desired.

' 20 designates a cable of any desired nature which passes over pulleys 21 and 66 and is ent furnaces. 24 designates an adjustable counterbalance for a damper 23. The lever 17 is also connected with an arm 25 which automatically controls the operation of a motor of any desired type but shown for purposes of illustration of the well known Spencer type which has been on the market for many years.

The lever 25 has one end thereof pivoted to a link 70, said link being also pivoted to an extension from the piston 112, with which latter cotiperates a valve stem 113, which is pivoted to'the lever 25. The motive fluid. is admitted to the piston chamber 114, through the valve controlled conduit 115, and isdischarged from the piston chamber through the conduit 116, which latter is pivoted to a lever 117 fulcrumed at 118 with a bracket 119, it being understood thatthe lever 117 has connected therewith the cable 20. The lever 117 is operatively connected witha valve 120 located in the steam conduit 28, which latter leads to the engine 29 controlling the operation of the fuel feeding mechanism, which for purposes of illustration, has been shown as consisting of a traveling grate 3. The steam conduit 28 is provided with controlling valves 30 and 31. A branch conduit 32 may also be provided, if desired, with a valve 26 which communicates with a conduit 27, which also communicates with the steam conduit posterior tothe valve 30, and said conduit 27 is provided with a controlling valve 121.

Each of the furnaces 1 is provided with a pressure regulator 33 of any desired or conventional type, but which for convenience of illustration, 1 have preferred to show as corresponding to one of my prior Patents 883,283, patented March 31st, 1908, except that I have shown in addition thereto a novel damping means,such .as is illustrated pressure. The member 34 includes an in-' .verted container 36 which extends into a container 37, in. which liquid, such as for example, water, is kept at a constant level in 'a manner hereinafter described. 38 designates an inner inverted container whereby an inner air chamber 39 is, formed and an outer air cushion'40. 41 designates a removable plug whereby the air cushion 40 may be varied. 42 .designates a valve controlled conduit communicating with a source of pressure sup ly, whereby the cushion 40 may be varied? 43 designates a conduit provided with a valve 44 communicating with the chamber 39 and also with the combustion chamber or heat zone 4 of the furnace. 45 designates an overflow pipe. 46 designates an arm connected with the member 34 to move-in unison therewith and also provided with a valve stem 47, which controls the valve mechanism 48, whereby the admission of mo tive fluid from the valve controlled conduit 49 to the motor 50 is regulated. The valve mechanism 48 admits motive fluid through conduits 51 and 52 to one side or the other of the piston 53, which latter is operatively connected with the cable 54 passing over the pulleys 55 and around a pulley 56, the latter pulley being operatively connected with a damper 57. 58 designates an adjustable counterbalance for the cable 54. The valve mechanism is provided with an overflow pipe 59 discharging into the container 37,

whereby the liquid therein is maintained at a constant level in order toseal the lower ends of the inverted containers 36 and 38.

scribe in detail herein, so that I have illus trated practical ways of varying the conditions within a furnace, for example, by

control of the induced draft. The mechanically induced draft, if employed, may be formed by providing the individual exhaust conduit 7 of a furnace with a by-pass 60 and a manually controlled valve 61. Lo-. cated in the by-pass 60 is a suction creating device, shown as a conventional type of a blower driven by an engine 63, to which steam is conducted through the conduit 27 The engine may be provided with a governor ,64 of anydesired or conventional type, whereby the engine may be run at a substantially constant speed. If the valve 26 in conduit 32 is closed, the steam will pass through the conduits28 and 27 to the engine 63, so that the engine will run ata constant speed. The governor- 64 maybe disconnected, however, the valve 121 closed and valve 26 opened, whereupon the speed of the engine. will vary in accordance with variaduced draft may be produced by any desired type of mechanism and still be within the broad and generic scope of my invention.

In case the individual conduits 7 discharge into a main exhaust conduit 71, as

seen in Fig. 8,"the suction creating device, such as forexample 65, would be located posterior to a manually controlled damper 72, having a pulley 73 provided with a counter balance 74, said pulley 73 being adapted to-be operated by a suitable cable corresponding to the cable 75 seen in Fig. 1.

This cable 75 passes over pulleys 76 and is connected with a pulley 7 carried by a damper 78 and provided with a counterbalance 79. 80 designates a manually conthe ash pit 2.

The only difference between the construction set forth in Fig. 1 and that in Figs. 5 and 6 is that in Fig. 1, the fuel is automatically fed into the furnace, and such feeding is automatically controlled in accordance with variations in load on the furnaces, while in Figs. 5 and 6, the furnaces are hand fired, it being understood that any desired type'of means for varyingthe conditions '90 trolled hand damper to close the rear end of within the furnace, such as for example,

that seen in Figs. 2 and 4, is intended to be employed, if desired, in connection with the exhaust conduits seen in Figs. 5, 6, and 7, and it also being understood that these exhaust conduits may discharge into a main exhaust conduit, such as 71, seen in Fig. 8, in which case the meansfor mechanically inducing the draft would be located in such main exhaust conduit.

In order to prevent confusion, the construction in Figs. 5 to 7 inclusive have been given different reference characters, although similar parts in these figures and in Fig. 1, correspond in construction and operation. 81 designates-the main draft conduit provided with a manually controlled damper 82 and -also with branch conduits 83, each of which communicates with the ash-pit of its respective furnace. Since each furnace is constructed and operated in a similar manner, Ihave deemed it to be unnecessary to describe .in' detail the construction and operation of each mechanism. For convenience of illustration, I have shown four furnaces 84, 85, 86 and 87, although it is to be understood that a single furnace or any number of furnaces may be employed in tive combustion chamber or heat zone 89.

The construction and operation of the pressure regulators 88 correspond to that already herein set forth with reference to Figs. 1 and 3. Each pressure regulator has the motor thereof operatively connected with a damper 90 in a branch conduit 83 and provided with an adjustable counterbalance 91. 92 designates a manually controlled damper, one being provided for eachbranch conduit 83. The draft'under its natural or atmospheric pressure passes into the ash-pit 93 beneath the bed :of. fuel 94. It will be seen that the'bed of fuel in each furnace is of a difierent thickness, thus corresponding to conditions met with in practice and furnace operations. Each furnace has a damper 95 provided with a pulley 96, adjustable counterbalance 97 and a cable 98, whereby each damper 95 may be manually opened or closed when desired.

. The exhaust conduits 99,- in which are located the hand dampers 95, are also provided with dampers 100, which are simultaneously actuated either manually or automatically in accordance with variations in load on the furnaces. The dampers 100 are provided with pulleys 101, with which cofiperate cables 102 and counterbalances 103, said cables 102 being connected with.

pulleys 104: mounted on the shaft 105. The shaft 105 has also mounted thereon a pulley 106, around which passes or to which is connected a cable 107, said cable being also connected with a pulley on the shaft 105. The cable 107, at its other end, is connected with a lever 108, corresponding to the lever 117,

seen in Fig. 1, it being understood that a steam regulator corresponding to the regulator 14 in Fig. 1, is employed, connected to'the main headerin a similar manner to that seen in Fig. 1, and operating in the 1 same .manner and including, if desired,

means for mechanically inducing adraft.

The operation of my novel method of regulating combustion will now be readily apparent to those. skilled in this art, and is asfollows:

rality of fires with beds of fuel ,of dilferent.

- and varying thickness, so that a thick'fire will produce the same result and the same I am also enabled to maintain a' fixed and uniform dif-,

amount of work as a thin fire.

ference of the pressure above and below the of the beds of fuel, so that a bed of fuel a i foot thick, for example, will perform the same amount of work asa bed of fuel three inches more or less in thiclmess.

In the position ofthe parts seen in Fig. l and Figs. 5 and 6, the dampers 23 in Fig. 1, and 100 in Figs. 5, 6 and 7 are shown in their wide-open position. .Assumingfor purposes of explanation that these dampers are closed, as well as the dampers57 and 90, and that the load-on the furnace increases or in other words, the steampressure lowers, the following action takes place. I The steam regulator 14 is actuated in such a manner that the motor levers 17 and 117 are moved in a directionto open the dampers 23, or the corresponding lever 108 is moved in a direction to open the dampers 100, the

amount of such opening depending upon the amount of variation inload on the furnaces. This movement of the dampers .23 and 100 will change the conditions within each furnace, since the exhaust conduits, such as 7 or 71, are opened to atmospheric pressure. As soon as the conditions within the furnace or the heat zone thereof begin to change in the manner just described, each pressure regulator 33 or 88 will be actuated in such a manner as to operate the dampers 57 or 90 and permit an increased amount of draft for combustion to enter the ash-pit beneath the bed of fuel. On a decrease in load on the furnaces or an increase in-steam pressure, a reverse action to that just described takes place.

, The operation of the motor controlled by the steam regulator 14 is well lmown in the art, it being seen that the piston ,112 andits adjuncts travel upwardly .or downwardly, according to the pressure. -Motive fluid is admitted to the valve controlled conduit 115. The admission of motive fluid from the valve controlled conduit 115 to one side or the other of the piston 112, is controlled by the position of the -valve stem 113. The movement of said valve stem 113, is controlled by the movement of "the lever. 25, which moves in unison with the lever 17, so that upon the movement of the steam regulator 14, the lever 117is moved in a corresponding direction to. actuate the cable 20 and thereby simultaneously and automatically actuate the dampers 23 in thedifierent.

exhaust conduits 7. It will be understood. that upon the movement of the steam regulator 14 and the movement of the lever 117v that the valve 120 is also actuated, so that the engine 29 may be automatically con trolled in accordance with variations of load on the furnace and the engine 63 may alsobe automatically controlled, if desired, in accordance with variations in load on the furnace. I 7

It.w'i1l be understood that in case a main exhaust conduit is employed, as seen in Fig;- 8, that the damper such as 23 is located between the suction creating device 65 and 7' nae-2,215

offered to the admission of draft for com:

bustion varies on each furnace, and an individual pressure regulator 1s employed for I each furnace which automatically controls the introduction of draft for combustion to each individual furnace, in accordance with the resistance offered to the draft by the thickness of the bed of fuel alone, the position of the damper alone, or the resistance ofi'ered by a combination of such conditions.

In 'my present invention, it will be seen that I have dispensed with the necessity of employing mechanically forced draft for combustion, and the furnace or furnaces are operated under van induced draft, which may be'either naturally or mechanically induced, as desired, although it"will be apparent that in the, broad scope of my invention, either a natural or mechanically induced draft can be used.

In cases wherein the fuel is mechanically fed to the fires, I preferably employ means to automatically control the operation of the engine, and in the present instance, I have shown one manner of accomplishing this result, by operatively connectingcthe lever 117 of the motor to the valve 120;*Whereby the passage of steam to the engine 29, which drives the traveling grate 3, is automatically controlled in accordance with the variations in load on the furnace. It will also be seen that the engine 63 or the steam injector 65 may be automatically controlled in accordance with variations in load on the furnace,

or may run at constant speed.

fuel, as seen in conjunction with the furnace 87 as I am with the beds of fuel seen in the other furnaces 84, 85 and 86.

The manually controlled dampers 78 or 95 are to permit an individual furnace to be cut out when desired. The automatically controlled dampers in the exhauts conduits are located posterior to the manually controlled dampers in such conduits and are located anterior to the means employed for mechanically inducing the draft.

Instead of automatically varying the conditions within thefurnaces, such conditionsmay be varied manually by leaving the dampers 23 and 100 in their wide-open posi-- tion, after which the dampers 7 8 or 95 may be manually operated to vary the condi tionswithin each furnace, whereupon the draft for combustion will be automatically ditions and in accordance with the varying thickness of the beds of fuel.

Special attention is directed to the fact that in accordance with my present invention, I am enabled to eliminate entirely the manual control of the draft for combustion and maintain the same rate of combustion on all the fires regardless of e difi'erent thick-- ness of the various fires and the entire operation is preferably automatic, Both the exhaust dampers and the fuel feeding means, when the latter are employed, are preferably automatically controlled by variations in steam pressure and the admission of draft in each bed of fuel is automatically controlled by varying conditions within the heat zone of its respective furnace above the bed of fuel. As thebed of fuel increases in thickness, it is necessary to increase the intensity of draft to maintain the same rate of combustion, and in order to maintain a .uniform condition of pressure above the bed of fuel, the pressure regulator, as the pressure andwthe combustion chamber or heat zone of the furnace decreases, is actuated in a direction to increase the intensity of draft below the bed of fuel and thereb increase the combustion. By such means, I maintain a fixed and constant difi'erence between the pressures above and below the bed of fuel and substantially the amount of air necessaryto support the combustion to meet the demands for steam or load on the furnace will be supplied and no more. Each fire is thus made to perform its share of the work, the result of which is that a maximum furnace eficiency is obtained, which is not interfered with by the fireman or engineer attempting to manually control the dampers, whichoontrol introduction of draft beneath each bed of fuel.

Wit

In methods heretofore employed in this art, it has been deemed impracticable to obtain a uniform rate of combustion in each are furnace owing to difi'erent causes, such as I for example, the difierence in thickness of the difi'erent fires, the constantly changing thickness of all fires, and the inattention of a fireman to properly adjust the hand damper admitting and controlling the draft to meet the requirements of the changing conditions of each fire.

In mypresent invention, a thick fire ofi'ering more'resistance to the draft automatically receives a greater intensity of draft in the ash-pit, while the draft on athin fire is correspondingly cut down.

I have referred herein to draft pressure of tension, but is tosbe understood that the draft introduced beneath the bed of fuel for primary combustion is at its natural pres-v sure or atmospheric pressure and the pres sure in the combustion chamber of heat zone of the furnace is a relative pressure but lower than atmospheric, and is commonly referred to as the vacuum above the fire.

I have deemed it unnecessary to illustrate and describe in detail a specific construction employed to carry out my novel method in case liquid or gaseous fuel or a combination of such are employed instead of solid fuel or any combination of solid, liquid or gaseous fuel, since the manner of carrying out the method is the same as herein already described and will be clearly understood by any one skilled in this art.

It will be seen from Fig. 5 that the osition of the dampers 90 vary in accor ance with the thickness of the bed of fuel, the furnace 87 having its damper 90 wide open, while the dampers 90 in the other furnaces are partially closed, depending upon the thickness of each bed of fuel.

It willbe understood from Fig. 1 that valve controlled conduits 109, 110 and 111 lead from the steam conduit 28 to the engines of the fuel feeding means of the different furnaces so that the fuel feed of each furnace is automatically controlled in accordance with variations in load on the furin a furnace operating pressure thus produced within the furnace.

2. The method of regulating combustion in a furnace operating under an induced draft, which consists in varying the pressure within the furnace in accordance with variations of load on the furnace, and automatically regulating the introduction of draft under its natural or atmospheric pressure in accordance with the variations of pressure thus produced within the furnace, and in accordance with the varying resistance oifered the introduction of the draft beneath the bed of fuel.

3. The method of regulating combustion in a furnace operating under an induced draft, which consists in mechanically inducing a draft, varying the pressure within the ace in accordance with'variations of load on the furnace, and automatically regulating the introduction of draft under its natural or atmospheric pressure in accordance with the variations of pressure thus produced within the furnace.

4. The methodof regulating combustion in a furnace operating under an induced draft, which consists in varying the pressure within the furnace in accordance with variations of load on the furnace, automatically regulating the introduction of draft under its natural or atmospheric pressure in accordance with the variations of pressure thus produced within the furnace, and automatically varying the fuel feed in accordance with variations in load on the furnace.

5. The method of controlling combustion in furnaces, which consists in varying the pressure above the fire to vary the rate of combustion on all the fires simultaneously and proportionately to variations of load on the furnaces, and varying the admission of neously and proportionately to variations of load on the furnaces to vary the conditions of pressure within each furnace, and then automatically varying by means of such variations in pressure the introduction of draftfor combustion under atmospheric pressure to each individual fire in accordance with the thickness of its bed of fuel to maintain an equal rate of combustion on all the fires.

7. The method of controlling combustion in furnaces, which consists in varying the rate of combustion on all the fires, simultaneously and proportionately to variations of load on the furnaces to vary the conditions of pressures within each furnace, then automatically varying by means of such variation in pressure the introduction of draft for combustion under atmospheric pressure to each individual fire in accordance with the thickness of its'bed of fuel to maintain an equal'rate of combustion on all the fires, and automatically varying the fuel feed in accordance with variations of load on the furnaces.

8.. The method of controlling'combustion in furnaces, Which consists in mechanically inducing a draft posterior to the fire, automatically varying the effect of such draft on the combustion chamber to vary the pressure within each furnace above its bed of fuel, and then utilizing the variations in the I pressure thus produced to. automatically control the admission beneath the bed of fuel of draft under its natural on atmospheric pressure.

9. The method of controlling combustion in furnaces, which consists first in automatically varying the conditions within the furnace in accordance with variations of load on such furnace, and then utilizing the varying conditions within the furnace to automatically control the introduction beneath the bed of fuel of draft under its natural or atmosphericpressure and in accordance inducing a draft in the exhaust conduit of the furnace, automatically controlling the draft inducing mechanism, controlling the passage of unconsumed products of combustion through said conduit in accordance with variations in load on the furnace to vary conditions Within the furnace, and then utilizing the varying conditions within the furnace to automatically control the introduction of draft for combustion beneath the bed offuel.

11. The method of regulating combustion in furnaces, which consists in simultaneously varying the pressures within all the furnaces in accordance with variations in load on all the furnaces, and utilizing the varying pressure in each furnace to automatically control the introduction of draft for combustion under atmospheric pressure to the fire of its respective furnace, and automatically controlling the feed of fuel to all of the furnaces.

FRANCIS H. BROWN.

Witnesses:

' H. S. FAIRBANKS, C. D. MCVAY. 

